In the toad retinal pigment epithelium (RPE) eyecup it was demonstrated that interphotoreceptor retinoid-binding protein (IRBP) promotes the formation, as well as the release, of 11-cis retinal. In the experimentally detached skate retina system, the introduction of ligand-free IRBP purified from bovine retina to the subretinal space significantly increased the rate of rhodopsin regeneration and more than doubled the amount of rhodopsin reformed in the darkness as compared with controls in which IRBP content of the subretinal space was diluted as a consequence of detachment and no purified IRBP was added back. In the vitiligo mouse model of retinal degeneration, elevated retinoid leve were found in both the RPE and the liver. These results represent the first evidence of biochemical malfunction in this mutant and suggest that i the eye, the RPE is the primary site of the defect that leads to retinal degeneration. A -70 kDa glycoprotein binding both retinoids and fatty acids was purified to homogeneity from Drosophila melanogaster heads. A method was developed, using reverse transcriptase-polymerase chain reaction (RT-PCR), for the quantitation of IRBP message in small amounts of tissue such as a single mouse pineal gland. Three intracellular human B-cell proteins (-40, 72, and 74 kDa) that bind specifically to peptide 1169-1191, an immunodominant, uveitopathogenic determinant of bovine IRBP, were partially characterized by immunoblotting and microsequencing. The 40 kDa protein was identified as actin, and the 72 and 74 kDa proteins were determined to be members of the hsp 70 family. The 72 kDa protein had 40 percent homology with human hsp 72 from lung fibroblasts, and the 74 kDa protein had a high degree of homology with human hsp 78 glucose-regulated protein from liver. Elevation of serum antibody levels to hsp 70 were found to occur during ocular inflammatory episodes in patients with Behcet's disease.